Patent Documents 1 and 2 made detailed descriptions of the demerits in conventional inactivated vaccines or toxoids, as well as the current states with regard to the development of mucosal vaccines and immunoadjuvants.
As described in Patent Documents 1 and 2, the requirement of switching from a conventional vaccine of being inoculated subcutaneously or intramuscularly to a mucosal vaccine inducing the production of an IgA antibody on mucosa which is a natural viral infection route, is widely and profoundly recognized. Especially as a next generation vaccine in the 21st century, a mucosal vaccine inducing IgA antibody production, topical immunity or mucosal immunity is desired to be developed and brought into practical use all over the world, but it has not be achieved yet.
In response to these problems, the present inventors have invented an antigen-drug (AD) vehicle, which is a complex of a pulmonary surfactant protein B and/or a pulmonary surfactant protein C and a lipid(s), and a mucosal vaccine consisting of this AD vehicle and an antigen (Patent Document 1). The present inventors also found that by adjusting the weight ratio V/A of the AD vehicle amount (V) to the antigen amount (A), the selective production of an IgA antibody and the production of both IgA and IgG antibodies are convertible, and then developed a mucosal vaccine based on such action mechanism (Patent Document 2). Patent Documents 1 and 2 also disclose the effectiveness of fragments (peptides) of the pulmonary surfactant proteins B and C.
In addition, as a result of a study on various variants of pulmonary surfactant protein fragments for their antibody production enhancing effects, the present inventors have invented an AD vehicle comprising as a component a synthetic peptide KnLm (wherein n is 4 to 8 and m is 11 to 20) which, in spite that it is a smaller-sized peptide than the partial peptides disclosed in Patent Documents 1 and 2, has a potent antibody production-inducing or -enhancing effect, especially for an exclusive production of a secretory IgA antibody as well as an excellent and effective inductory effect on the production of both secretory IgA and blood IgG, and a mucosal vaccine consisting of this AD vehicle and an antigen (Patent Document 3).
In a nasal drop formulation whose administration route is identical to that for a mucosal vaccine, for the purpose of increasing the viscosity to sustain the efficacy against a pollinosis or an allergy, a carboxyvinyl polymer (CVP) or a hydroxypropyl cellulose (HPC) is employed widely and a thickening gelator such as sodium alginate is also employed. For example, an HPC-containing mucosal vaccine (Patent Document 4), a CVP-containing mucosal vaccine formulation (Patent Document 5) and an influenza vaccine for nasal spray (Patent Document 6) are also known. Patent Document 7 also discloses a mucosal vaccine consisting of an antigen, an adjuvant [especially Poly(I:C)] and a thickening agent (sodium alginate and the like).    Patent Document 1: WO 2005/097182    Patent Document 2: WO 2007/018152    Patent Document 3: WO 2009/123119    Patent Document: JP-A-2008-231343    Patent Document 5: WO 01/017556    Patent Document 6: JP-A-03-38529    Patent Document 7: JP-A-2009-209086